Synthetic lubricants



Patented Sept. 25, 1951 UNITED STATES PATENT OFFICE SYNTHETIC LUBRICANTSYork No Drawing. Application September 28, 1950, Serial No. 187,368

19 Claims.

This invention has to do with the preparation of synthetic lubricantsfrom normal, alpha monoolefins and, more particularly, has to do withthe preparation of lubricants from certain complex mixtures containingsuch olefins.

As described in several related and copending applications, identifiedhereinafter, it has been found that normal, alpha mono-olefins of variedchain length can be converted to excellent synthetic lubricants. Highviscosity indices, low pour points and/or superior stabilitycharacterize these lubricants. Not only have the individual normal,alpha mono-olefins proven of value in this regard, but mixtures of thesame have been found to be satisfactory. In addition, complex mixturescontaining substantial proportions of these olefins have been found tobe suitable starting materials. A source for the complex mixturescontaining these olefins is the, Fischer- Tropsch process and relatedprocesses. As is 'well known in the art the Fischer-Tropsch processinvolves reaction of carbon monoxide and hydrogen in the presence ofcobalt or chemically related catalysts, whereupon hydrocarbons,including oleflns and parafiins, and oxygen-containing compounds areformed. When the carbon monoxide to hydrogen ratio is increased, largerquantities of oxygen-containing compounds are generally formed.

While the foregoing complex mixtures are converted to syntheticlubricants of low pour point and high viscosity index, as described in,theapplications referred to above, certain constituents therein aredeleterious in reducing the yield and/or quality of the lubricants ifpresent in excessive amount. Undesirable constituents includenon-primary olefins, aromatics, naphthenes and paraflins;oxygen-containing compounds; suspended material, particularly metalliccatalysts and their compounds. With regard to quality of the lubricants,it has been found that they are characterized by considerable color.This is a serious shortcoming inasmuch as these highly coloredlubricants generally do not respond to conventional procedures, namely,filtration,

2 adsorption, etc., for removing color bodies. In addition, the carbonresidue values of thelubricants are relatively high. A furthershortcoming traceable to constituents of the complex olefinic chargestocks, is that the viscosity indices of the lubricants generally fallbelow those of the lubricants formed from individual normal, alphamono-olefins. Still another undesirable feature is in the relatively lowresponse of the lubricants to inhibitors, particularly oxidationinhibitors. This is well illustrated with an outstanding oxidationinhibitor comprising an oil-v soluble, phosphorusand sulfur-containingreac--v tion product of pinene and phosphorus pentasulfide, which isdescribed in detail in Patent No. 2,416,281. I

It has now been found that synthetic lubricants having good color, lowcarbon residues and substantial inhibitor response, in addition to lowpour points and high viscosity indices, can be obtained by treating theforegoing complex olefin charge with a solution of an alkali metal saltof a phenolic material, described in more detail hereinafter, whereby anolefinic rafilnate is obtained, and converting the olefinic raffinate toa synthetic lubricant by the procedures described in thefollowingapplications. I

In Patent No. 2,500,166, it has been shown that normal, alphamono-olefins having six to about twelve carbon atoms per molecule formsynthetic lubricants when heated at 500-750" F., in the absence of acatalyst. At temperatures of the order of 700-900 F., the use of a gassuch as hydrogen, carbon monoxide and mixtures of such gases, with theaforesaid mono-olefins makes possible the formation of syntheticlubricants in substantial yield. This is described in Patent No.2,500,159. The aforesaid mono-olefins are also converted to syntheticlubricants when contacted with lead tetra-acetate at elevatedtemperatures, particularly 400-700 F., as explained in Patent No.2,500,161. Another related development involves condensation, at SOD-750F. of an olefin mixture comprising ashort chain mono-olefin of 3 two tosix carbon atoms and a long chain normal, alpha mono-olefin of ten tothirty carbon atoms; the mean carbon chain length is maintained withinthe range of six to twelve carbon atoms by proper proportioning of theolefins. This is described in Patent No. 2,500,162.

Polymerization of the aforesaid mono-olefins of six to fourteen carbonatoms per molecule, in the presence of a paraffin at temperatures inexcess of 700 F., forms the subject matter of Patent No. 2,500,165.Monocyclic aromatics and/or naphthenes may be used in thispolymerization, in place of the parafiin, as shown in Patent No.2,500,244. Polymerization of said mono-olefins may also be accomplishedat temperatures within the range of 550'-750 F., using small amounts ofsulfur, selenium and/or tellurium; this is described in Patent No.2,500,164. Small amounts of sulfur, selenium and/or tellurium can beused also in converting polymeric materials of said mono-olefins, toexcellent synthetic lubricants, following the procedure explained incopending application Serial No. 148,504, filed March 8, 1950. Attemperatures of the order of 600-750 F., small amounts of phosphorussulfides affect the polymerization of the aforesaid mono-olefins; thisis described in Patent No. 2,500,163.

A catalytic conversion of normal, alpha monoolefins having from six toeighteen carbon atoms, to synthetic lubricants is described in copendingapplication Serial No. 776,428, filed September 26, 1947-, nowabandoned; the catalysts used are silica-alumina composites.

Styrene also reacts with the aforesaid monoolefins, at temperatures fromabout 500 F. to about 700 F., with the formation of syntheticlubricants, as shown in Patent No. 2,500,161. Conjugated hydrocarbonsand sulfur react with normal, alpha mono-olefins having from about fiveto about eighteen carbon atoms to form lubricants (Patent No.2,500,167). A related development involves reaction of conjugatedhydrocarbons, phosphorus sulfides and the corresponding mono-olefins ofsix to fourteen carbon atoms, as shown in Patent No. 2,500,247. Stillanother related development is that wherein lubricants are formed byreaction of vinyl-substituted aromatic compounds, thiols and normal,alpha mono-aloe fins, described in Patent No. 2,500,672.

In copending application Serial No. 673,892,

filed June 1, 1946, now 2,551,638, it is shown that normal, alphamono-'olefins having from about seven to about twelve carbon atoms permolecule react with organic peroxides at 120-570 F. to form syntheticlubricants. With the corresponding mono-olefins of six to eighteencarbon chain length, organic peroxides and halogenated olefins arereacted at 120-570 F. with the formation of lubricants; Serial No.776,427, filed September 26, 1947, now 2,551,640. As a relateddevelopment, organic peroxides, conjugated hydrocarbons and theaforesaid monc-olefins of from five to eighteen carbon atoms are reactedat 120-570 F. to form lubricants; Serial No. 53,372, filed October 7,1948,*2,551,641. Organic peroxides, aromatic hydrocarbons and saidmono-olefins of live to eighteen carbons also react to form lubricantsas described in copending application Serial No. 72,744, filed January25, 1949, now

2,551,642. Certain heterocyclic compounds may be used in place of thearomatic hydrocarbons in the last-mentioned development; this isexplained in copending application Serial No. 83,772, filed March 26,1949. Lubricants of high viscosity are formed by reacting the aforesaid4 mono-olefins of five to eighteen carbon atoms with certain unsaturatedesters and organic peroxides; copending application Serial No. 72,745,filed January 25, 1949, now 2,551,643.

Normal, alpha mono-olefms also react with olefinic mono-oxides and-su1fides at SOD-700 F. to form lubricants, as explained in Patent No.2,486,441.

It is to be understood, therefore, that the treated complex olefiniccharge may be converted to synthetic lubricants by any of the foregoingconversion procedures shown in the above-identified applications andpatents.

EXTRACTION TREAT As indicated above, the complex olefinic charge stocksare extracted with certain solutions of alkali metalsalts of phenolicmaterials prior to conversion to synthetic lubricants. The solutionsselectively extract and separate the various constituents of the rawmaterial. For example, oxygenated compounds and aromatic hydrocarbonsare separated from normal, alpha. mono-olefins present therein.

Solutions suitable for use herein are aqueous and/or alcoholic solutionsof alkali metal salts of mono-hydroxy aromatics represented by thegeneral formula:

wherein A is an aromatic nucleus such as phenyl, naphthyl, anthryl,etc., and is preferably phenyl; R is an alkyl group having less thanabout six carbon atoms, and is preferably methyl; and n is an integerfrom zero to 3, and is preferably one. Alkyl groups (R), when present,preferably have a total'number of carbon atoms of less than about six.Illustrative of such compounds are: phenol, m-cresol, o-cresol,p-cresol, and mixtures thereof such as Selecto mixtures, p-tertiarybutyl phenol, 2-4-x'ylenol, 2-3-xylenol, m-isopropyl phenol, etc.Particularly preferred, however, in View of its excellence herein, ism-cresol.

The alkaline constituent of the extractant is preferably potassium. Itcan also be any other.

alkali metal of Group I of Mendelejeffs Periodic Table, namely, lithium,sodium, rubidium and cesium. The concentration of the alkali metal saltin the solvent is preferably at its upper limit of solubility. However,it can be as low as 50%.

Low molecular weight alcohols such as methyl, ethyl, n-propyl and'i-propyl alcohols, are useful herein as solvents for the alkali'metalsalts. Liquid. polyhydric alcohols, such as the 'glycols, are alsoadvantageous. Suitable glycols include: ethylene glycol, diethyleneglycol, propylene glycol, dipropylene glycol and the like. The alcoholsan'd/or glyc'ols can be used alone or mixed with water.

Extractionof the complex olefinic charge can be effected in any one ofseveral Ways. For ex ample, the charge and extractant solution can beagitated in a suitable vessel; the resultant mixture can be allowed tosettle, whereeupon two layers form; and the olefinic layer or raffinatecan then be separated from the extract which contains the undesirableconstituents of the complex charge. Another typical operation is that ofcontinuous countercurrent extraction, in'much the same manner asconventional solvent extraction procedures for preparing lubricatingoils from oil stocks.

The ratio of charge stock to extractant soluquantity of extractantsolution required for a;

desired degree of improvement isdependent upon the quantity ofundesirable materials present in the complex olefinic charge. By way ofillustration, with a charge comprising about 60 per cent (by volume) ofnormal, alpha mono-olefins and about 40 per cent ofundesirablecomponents, appreciable extraction is obtained with about0.25 part of a concentrated extractant solution for each partof thecharge, or a ratio of 0.25:1 in a single stage operation. It ispreferred, however, that multiple stage operation be employed and thatthe over-all ratio be maintained from about 0.25:1 to about 4:1. 7

Temperaturesand pressures employed during the extraction do not appearto be critical. As a rule, however, low temperatures-of the order of25-75? C.are preferred.

The extracted constituents of the charge stocks used herein arepredominantly oxygenated materials and aromatic hydrocarbons, which arereadily removed from the extract when the latter is diluted with water,or topped out by distillation at atmospheric or reduced pressure. Asteam distillation of the oxygenated materials at moderate superheat ispreferred. The recovered materials-particularly, the oxygenatedcompounds--are highly effective and valuable solvents and chemicalintermediates.

The .olefinic rafiinate obtained in the extraction is thereafterconverted to a synthetic lubricant by any of the procedures described inthe aforementioned copending applications and patents. about 600 v1*".and boiling predominantly within the range 150-500 F., is suitable forconversion. It is to be understood, however, that fractions boiling overthis range and those boiling within a portion of the range can be soconverted. For example, fractions boiling from 200 F. to 300 F.

and from 300 F. to 450 F. have proven excellent charge stocks forconversion. The rafiinate fraction boiling from 300 to 450 F. contains asubstantial proportion of normal, alpha mono-olefins of nine to twelvecarbon atoms per molecule, and represents a preferred charge stockinasmuch as the synthetic lubricants obtained therefrom haveparticularly advantageous characteristics.

EXAMPLES.

The following examples serve to illustrate, and not limit, theinvention.

Example I Y A complex oleflnic charge stock obtained in aFischer-'Iropsch reaction with an iron catalyst A raflinate boiling fromabout 100 F. to 1 parts by 1 volume of a ,62. per centv (saturated)aqueous solution of vpotassiumsal-ts of a mixture ofgphenol and cresols(Selecto);.j The resulting mixture was allowed to settle, whereupon twolayers formed, a lower layer comprising the ex-f tract and an upperlayer comprising the finate. The layers were separated.

The rafiinate layer, comprising the olefinic portion of the complexcharge stock, was then treated in a'similar manner with seven successiveportions of the aqueous potassium salt solution. The raifinate finallyobtained was washed; with a 5 percent aqueous sodium hydroxidescilution. (600 parts by volume) to remove and recover phenol andcresols of the extractant. Following this, the raffinate was washed withwater (2400 parts by volume) and filtered through paper. The raffinate,now neutral to litmus, comprised 704 parts by weight. The rafiin'atecontained 72% olefins plus paraflins, about 26.5 per cent of aromatichydrocarbons and about-1.'5% oxygenated compounds.

;, The olefinic raifinate was charged to a bomb and the atmospheretherein was replaced with.

nitrogen. The bomb was then heated at about 652 F. for about ten hours,with additional time required to heat the bomb to this temperature andto cool the bomb. The bomb was discharged and the contents were vacuumdistilled at a max-.

imum vapor temperature of 356 F. at 3 mms. (Hg) pressure, to recover themore volatile materials. The remaining product was filtered. Todistinguish the conversion product from the distillate product, therefined oil is defined as residual oil. The latter term identifies theoil from which unreacted materials and products of intermediate boilingrange have been separated.

The residual oil comprised 207 parts by weight,

The oxidation tests used reveals the stability of oils toward catalyticoxidation. The test oil, 25 00s., is placed in a 200 x 25 mms. test tubewith 15.6 square inches of sand-blasted iron wire, 0.78 square inch ofpolished copper wire, 0.87 square inch of polished aluminum wire, and0.167 square inch of polished lead plate. Dry air is passed through thesample of oil at a rate of 10 liters and having the followingproperties, was selected:

A quantity, 750 partsby weight, of the olefinic charge was'agitated forabout five minutes, at

room' temperature (20'-25 C.) with about 250 erence oil of similarviscosity and is rated on the basis of viscosity increase, N.N.increase, sludge raf- - Treated Untreated Resldual on Charge ChargeYield, Wt. Per Cent 27.6 28.0 Specific Gravity 0.8713 0.8762 API Grevit30. 9 30.0 Pour Point, +5 K.V. at 100 F., Cs 26.20 37.79 K.V. at 210 F.,CS .l 4.85 6.01 Viscosity Index 120. 3 113. 5 Lovibond color 33 100 N0.2 0.3 0.2 0.2

per cent c l s 1 1 Analysis of oil after 0.5 12.0 4. 89 12. 39 0.8 104O. 9 132. 3 Nil Dark Blacl Red, Black It is apparent that the treatedcharge stock, when converted, yields a residual oil of higher viscosityindex and better color than does the untreated charge. Notable, too, isthe superior oxidation stability of the residual oil obtained from thetreated charge.

Example II Evaluation of the extractant solutions, and of relatedmaterial which proved of little value, was based upon miscibilitystudies. The extractants were made by first dissolving the alkalineagent in a solvent and then adding the phenolic compound in equimolarproportion. In cases where complete solution was not attained at roomtemperature (25 C.) additional solvent was added until the resultingsolution became clear. The calculated concentration of the salt takesinto account the water of formation from the neutralization. Forexample, Run

4 shown in Table I below,- can be represented as follows:

OH OK CH3 CH3. 320 KOH H2O 62 108 g. 56 44 146 g. A The concentration ofthe salt is therefore 70% in water. I, Extractions were conducted byadding 10 parts by volume of petroleum ether, benzenedecanol, n-decene-lor a Fischer-Tropsch product, as

indicated in Table I, to '10 parts by volume of" the eXtractant in avessel having a capacity of 25 parts by Volume and calibrated to 0.2part. The vessel was then closed and the contents agitated for aboutthirty seconds. The vessel was set at rest at room temperature (unlessotherwise indicated) until equilibrium was reached, usually less thanthirty minutes. The change in volume of the two layers in the vessel wasthen noted. Since the vessel is calibrated to 0.2 part, theresults areaccurate to about one per cent.

The Fischer-Tropsch product used in this investigation Was one havingthe following properties:

Boiling range:

ASTM, "F 280-574 50% point, F 41 6 Specific gravity 0.8137 Brominenumber 72.5

oxygenated compounds (Adsorption analysis), percent 14 Aromatics,percent Olefins and paraffins, percent 66 As indicated, the 50% point inthe ASTM distillation was 416 R, which corresponds to a boiling point of419 F. for n-dodecene-l. Therefore, n-decene-l and decanol arerepresentative of some of the olefins and oxygenated compounds which arepresent in this complex olefinic charge, while petroleum ether andbenzene are representative of the general class of paraffins andaromatics.

The results of these extractions are shown below in Table I.

TABLE I Preparation of eztractant and extractions (m petroleum ether,benzene, declmol, deems-' and Fischer-Tropes]; charge Extractant PageReferencc Acidic Component Alkali Solvent Name Parts by Wt.

Name gi: by Moles Name H 04, 96% l 1131 04, 85% .l Sodium xylenesullonate. meta-Crcsol ..do

None meta-CresoL None para-telrtiary-Butyl phenoL en Selecto RcsorcinolK211 P 04 Propionic acid Lactic acid 1 Composite of ASTM boiling'range280-574 F., cf. p. 375, 346.

5 60% phenol, cresylic acid.

TABLE I-Gontinued Extractions (1:1 Volume Ratio)' Volume Per Cent v PExtractant Extracted Fromage Number Referd ence CalculateFischersggglcilalfgtgt zi g f gggg Benzene Decanol Decene- 'Irlogrsgi 0Gel 100 50 0 0 Gel 0 4 0 2 Gel 0 0 0 O 100 0 l3 I- 100 100 100 100 100 00 Gel 0 1 0 0 Gel 0 4 0 0 Gel 0 4 100 100 0 12 0 0 100 0 3 0 20 Gel 0 2040 100 6 17 100 100 10 100 100 100 22 10 20 Gel 4 20 0 0 Emulsion 0 4 00 Gel 0 4 8 80 100 4 25 0 l0 100 0 l5 (Monosalt) 70 0 0 O 0 0. (Di salt)70 0 0 0 0 62 0 O 0 0 0 70 O 0 0 0 0 70 0 0 0 0 0 FComposite of ASTMboiling range 280-574 F., of. p. 375, 346.

.7 Very viscous solution heated to 65 C. for extractions.

solidified on standing.

From the results in Table I, several observations can be drawn. As wouldbe expected, cold concentrated sulfuric acid (No. 1) had no efiect u onpetroleum ether and benzene, but reacted vigorously with decanol,n-decene-l and the complex olefin charge, as indicated by darkening andheat evolution. Upon standing, of the complex olefinic charge separated.

Ortho phosphoric acid, 85% (No. 2), appears to be selective foroxygenated compounds. However, considerable darkening occurred in thecomplex olefinic charge. This is an undesirable feature since itindicates that at least some constituents have reacted and therefor arenot directly recoverable.

Sodium xylene sulfanate (No. 3) failed to extract any material from thecomplex olefinic charge. Its solubility in water at 25 C. is only 47.6%however It extracts only a small amount (2%) from benzene and gelledwith 'decanol (indicating some solubility).

several extractants, and is preferred herein. It

is selective for decanol and extracted 13% of th'e complex olefiniccharge. m-Cresol alone (No. 5) had no selectivity under the operatingconditions, that is, it had no selectivity for compounds of suchrelatively low molecular weight. A 56% solution of potassium hydroxidein water (No. 6) had practically no extracting power. A 48% solution ofpotassium m-cresylate in water (No. 7) exhibited slight extracting power(4% of the complex olefinic charge), indicating that the moreconcentrated solutions are more advantageous. The sodium salt ofm-cresylate (No. 8) is soluble in water only to the extent of 48%, thuslimiting its efiectiveness.

V In No. 9, triethylene glycol was used as the solvent with potassiumm-cresylate. The potassium salt was soluble when present in the amountof 70%; however, the solution was quite viscous. Dilution to a 50%concentration decreased the viscosity somewhat but it was stillnecessary to heat the extraction mixture to 65 C. to obtain intimatemixing. The extractant was .matic and oxygenated compounds.

then selective for benezene and decanol and extracted 12% of the complexolefinic charge. The glycol type solvent, therefore, increases thesolubility of aromatic hydrocarbons in the extractant.

A 70% solution of potassium o-cresyljate in water-No. l0-was selectivefor decanol, and extracted 3% of material from the complex olefiniccharge. It is, therefore, less effective than the correspondingm-cresylate. Potassium p,- cresylate (No. 11) was somewhat less solublein water (66%), but partially dissolved both benzene and decanol andextracted 20% of the complex olefinic charge. The latter extractant istherfore advantageous for extracting both aro- By using methyl alcohol,along with or in place of water, as the solvent, the solubility ofbenzene is 'increased further (Nos. 12 and 13, respectively). Thesolubilities of petroleum ether and ndecene-l also increase, although toa lesser extent. Methyl alcohol used alone as an extractant exhibitslittle selectivity (No. 14). v p The potassium salt of p-tertiary butylphenol (No. ,15) is slightly less soluble inwater than is the'potassiumsalt of p-cresol. Its extracting power is also somewhat difierent, forit partially dissolves petroleum ether and n-decene-lin addition tobenzene and decanol. However, it extracts 20% of the complex olefiniccharge, thus indicating its extracting capacity.-

A saturated aqueous solution of potassium phenate (No. 16) shows somecapacity to dissolve decanol and extracts 4% of the complex olefiniccharge. A saturated aqueous solution of the potassium salts of a mixtureof phenol and cresols (No. 17), known in the art as Selecto andcurrently used in the Duo-Sol process, provides similar results. Byusing methyl alcohol as the solvent (No. 18) the solubility of each ofthe constituents is increased.

The potassium salt of 2,4-x'ylenol"(No. 19) is quite soluble in water.It is selective for both decanol and benzene, and extracts 15% of thecom plex olefinic charge.

The succeeding examples failed to exhibit extracting power, as did No. 3(sodium xylenesulfonate) and No. 6 (potassium hydroxide), referred toabove. The monoand .di-potass'ium salts of resorcinol (Nos-20 and 21,respectively) are soluble in water, but extract nothing from petroleumether, benzene, decanol, n-decene-l or the complex charge. Catechol,'hydroquinone and pyrogallol would not form clear potassium saltsolutions because of their tendency to oxidize, as evidenced by therapid darkening of color and precipitation of oxidation product.

Saturated aqueous solutions of K2HPO4 (No. 22), a 70% solution ofpotassium propionate (No. 23) and a 70% solution of potassium lactate(No. 24), also failed to extract any material from petroleum ether,benzene, decanol, ndecene-l and the complex charge.

Six of the foregoing extractants which exhibit varying degrees ofeffectiveness were used to extract the complex olefinic charge. A 2:1(total) volume ratio of extractant solution to charge was used,following the procedure described in Example I above. The rafiinate ineach instance was finally water washed, filtered through paper andpercolated through silica gel (as described in pending applicationSerial No. 144,912, filed February 18, 195.0). Results of theseextractions are provided in Table II following.

TABLE II Adsorption Analysis of Rafiinate, I Vol. Per Cent No. in TableExtracting Solution I Olefins Aromatic' Oxyzenated and Com- Com-Paraflins pounds pounds None '66 20 14 4 70% K m-Oresylate, 78 22 0 H20.4A 70% K m-Cresylate 76 24 '0 ill. 351 20. '9 50% K In-Cresylate; '80'20 0 44% Triethylene: Glycol 6% 1120. I0 70% K o-Cresylate 76 22. 4 1.6

111 H20. .16 62.5% K phenate in 71 24 H20. '17 62% K salt of Se- 72 26.51.5

lecto in 1120. 18 54% K salt of Se- 85 O l'ecto, 28% OHZOH and 8% H20.

' Extraction made at'4550 C. 'Extraction made at 6575 C.

It will be noted thatall of the .examples shown in Table II demonstratea selective extraction capacityof the several solutions therein. In allmove some undesirable materials and the acidtreated stock is convertedto a lubricant, the latter either .fails to exhibit response or has buta very minor response. This also obtains when the stock is treated withan alkaline material, either in solution or in solid form. The oilsobtained following an acid, or alkaline treat, however, arecharacterized by desirable properties, namely, low pour point, highviscosity index, good color and low carbon residue.

It is to be understood that the foregoing specific treating conditionsand examples serve to illustrate the invention, for it will be apparentto those skilled in the art that modifications and variations thereofmay be used. It is to be understood, therefore, that such modificationsand variations fall within-the scope of the appended claims, and thatthe invention is to be construed broadly in the 'light of the languageof the appended claims.

We claim:

1. A process for preparing a synthetic lubricant from an olefinic chargestock obtained by a Fischer-Tropsch reaction and having a substantialportion boiling within the range of about 150 F. to about 600 F., saidlubricant .having goodcolor, low carbon residueand having inhibi--cases,.oxygenated compounds are extracted from the complex olefiniccharge. A solution of potassium m-cresylate in water (Nos. 4 and 4a.) isagain shown to be outstanding.

Although the invention has been described above with emphasis uponcertain complex olefinic charge-stocks, the extraction procedurecontemplated herein is also advantageous for beneficiating othercomplexmixtures containing oxygenated compounds having a molecularweight tor response with an oil-:soluble, phosphorusandsulfur-containing reaction product of pinene and PzSs, which comprises:contacting said charge stock witha substantiallysaturated solution of analkali metal salt of a mono-hydroxy aromatic compound represented by thegeneral formula RmAOH wherein A is an aromatic nucleus, R is an alkylgroup having less than about 6 carbon atoms, and n is an integer 'from 0to 3, whereupon an extract layer and a raffinate layer are formed;separating said extract and raffinate layers; and converting saidrafiinate layer into said synthetic lubricant.

.2. .Theprocess of claim 1 wherein the charge stock is one .boilingpredominantly within the range of about200 F. to about 300 F.

3. The process of claim 1 wherein the charge 1 stock is one boilingpredominantly within the range of about 300 F. to about 450 F.

4. The process of claim 1 wherein the ratio .of said charge stock tosaid solution is between about 0.25 and about 4.

5. The process of claim 1 wherein the solution is a substantiallysaturatedaqueous solution.

6. The process of claim 1 wherein the solution is a substantiallysaturated, aqueous alcoholic solution.

'7. The process .of claim 1 wherein the alkali metal salt is potassium.

8. The process of claim 1 wherein the monohydroxy compound contains aphenyl group.

9. The process of claim 1 wherein the monohydroxy'compound is m-cresol.

10. Theprocess of claim 1 wherein the solution is a substantiallysaturated solution of potassium m-cresylate.

11. The process for separating oxygenated organic compounds and olefinsfrom an olefinic mixture obtained by a Fischer-Tropsch reaction andhaving a substantial portionboiling within the range of about F.to-about 600 F.,-which comprises: contacting said mixture with aisub-.stantially saturated solution of an alkali metal salt of a mono-hydroxyaromatic compound represented by the general formula Rn-AOH wherein A isan aromatic nucleus, R is an alkyl group having less than about 6 carbonatoms, and n is .an integer from :0 to 3, whereupon an extract layer anda raflinate layer are formed; separating said extract and rafiinatelayers, said extract layer being richer in said oxygenated compoundsthan the original olefinic mixture, and said raflinate layer beingricher in olefin content than said original olefinic mixture.

12. The process of claim 11 wherein the olefinic mixture is one boilingpredominantly within the range of about 300 F. to about 450 F.

13. The process of claim 11 wherein the solution is a substantiallysaturated aqueous solution.

14. The process of claim 11 wherein the solution is a substantiallysaturated, aqueous alcoholic solution.

15. The process of claim 11 wherein the alkali metal salt is potassium.

16. The process of claim 11 wherein the monohydroxy compound contains aphenyl group.

17. The process of claim 11 wherein the monohydroxy compound ism-cresol.

18. The process of claim 11 wherein the solution is a substantiallysaturated solution of potassium m-cresylate.

19. The process for separating an oxygenated organic compound and anolefin of similar boiling point and having a molecular weight from about30 to about 300, from a mixture containing the same, which comprises:contacting said mixture with a substantially saturated solution of analkali metal salt of a monohydroxy aromatic compound represented by thegeneral formula Rn-.AOH wherein A is an aromatic nucleus, R is an alkylgroup having less than about 6 carbon atoms, and n is an integer from 0to 3, whereupon an extract, layer and a rafi'inate layer are formed;separating said extract and raffinate layers, said extract layer beingricher in said oxygenated compounds than the original olefinic mixture,and said rafiinate layer being richer in olefin content than saidoriginal olefinic mixture.

THOMAS F. RUTLEDGE. FRANCIS M. SEGER. ALEXANDER N. SACI-IANEN. WILLIAME. GARWOOD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,822,016 Daniels Sept. 8, 193125 1,877,614 Stratford et al. Sept. 13, 1932 2,139,000 Cohen Dec. 6,1938 2,146,650 Pokorny Feb. 7, 1939

1. A PROCESS FOR PREPARING A SYNTHETIC LUBRICANT FROM AN OLEFINIC CHARGESTOCK OBTAINED BY A FISCHER-TROPSCH REACTION AND HAVING A SUBSTANTIALPORTION BOILING WITHIN THE RANGE OF ABOUT 150* F. TO ABOUT 600* F., SAIDLUBRICANT HAVING GOOD COLOR, LOW CARBON RESIDUE AND HAVING INHIBITORRESPONSE WITH A OIL-SOLUBLE, PHOSPHORUSAND SULFUR-CONTAINING REACTIONPRODUCT OF PINENE AND P2S5, WHICH COMPRISES: CONTACTING SAID CHARGESTOCK WITH A SUBSTANTIALLY SATURATED SOLUTION OF AN ALKALI METAL SALT OFA MONO-HYDROXY AROMATIC COMPOUND REPRESENTED BY THE GENERAL FORMULARN-A-OH WHEREIN A IS AN AROMATIC NUCLEUS, R IS AN ALKYL GROUP HAVINGLESS THAN ABOUT 6 CARBON ATOMS, AND N IS AN INTEGER FROM 0 TO 3,WHEREUPON AN EXTRACT LAYER AND A RAFFINATE LAYER ARE FORMED; SEPARATINGSAID EXTRACT AND RAFFINATE LAYERS; AND CONVERTING SAID RAFFINATE LAYERINTO SAID SYNTHETIC LUBRICANT.